The AAC Blackout Flash Hider is engineered for serious suppressor users who demand reliable repeatable mounting performance. Featuring a 1x16 left-hand threaded taper mount interface and 1/2x28 threading for 5.56/.223 caliber firearms.AAC Blackout Flash Hider with Taper Mount Interface1x16 Left-Hand Threaded Tapered Mount for secure suppressor attachmentPrecision taper interface ensures consistent mountingCompatible with 5.56 NATO and .223 Remington calibers1/2x28 barrel threadingBuilt for suppressed use under demanding firing schedulesDesigned for shooters who actually run suppressors in the field this muzzle device delivers the secure repeatable mounting performance that stays put when it matters most.